Today, power generation plants are being designed for more demanding operating conditions, such as higher pressure and temperature conditions. These new designs create new balancing problems at a time when most power generation plants must operate at peak capacity with a minimum of downtime.
An increasing awareness of the negative effects of vibration on plant efficiency and reliability has led engineers to remove plants from service once vibration-related problems are detected in order to avoid more costly forced outages. These preventive maintenance programs require measurement of shaft vibration to test for abnormal dynamic operating conditions, such as unbalance.
Unbalance is the most common vibration related problem and causes stress in the rotor and its support structure which can result in (1) excessive wear of bearings, seals, couplings and gears; (2) fatigue failure of rotating components, such as shafts, blades and impellers; and (3) fatigue failure of stationary structures, such as bearing pedestals and stator frames. Correcting dynamic unbalance can increase plant efficiency and extend the useful life of power generation equipment.
Data acquistion devices are used in the industry to provide maintenance technicians and engineers with information needed to quickly and accurately balance rotating machinery on-site. Many of these devices are capable of receiving input on multiple input channels, but are capable only of acquiring data on a single input channel at any given time.